The present invention relates to a longwall mining machine of the type having a pivot arm which supports a cutter drum for rotation about an axis for working a mine face. A cowl or clearing shield is positioned at a desired location about the periphery of the cutter drum, specifically on the side of the drum opposite the face being mined. In a mining machine of this type, the rotating cutter drum cuts the material being mined and is provided with spirals which assist in loading the mined material onto a face conveyor. Loading efficiency is improved with the use of the cowl which comprises an arcuate plow which follows behind the cutter drum and which can be pivoted from one side of the drum to the other, depending upon the direction of movement of the mining machine.
In a mining machine of the type described above, the cutter drums often carry nozzles on the periphery of their spiral conveying flights for directing a trickle of liquid onto the face area being mined. The flow of liquid to the nozzles is controlled by valves spaced around the axis of the drum; and these valves are actuated such that liquid is delivered only from those nozzles immediately adjacent the working face.
In U.S. Pat. No. 1,473,498, a cutter drum assembly for mining machines is disclosed wherein the nozzles on the periphery of the cutting drum are connected through conduits and valves to a source of liquid under pressure, these valves being actuated to deliver liquid to the nozzles immediately adjacent the working face by a cam which does not rotate with the cutter drum itself.
In German Offenlegungsschrift No. 2,808,915, a cutter drum assembly is disclosed wherein water under pressure is supplied only to spray nozzles on the drum periphery near that sector of the drum which is actually cutting, and wherein that portion of the drum periphery opposite the face area is covered by a cowl. The cowl is arranged to pivot around the rotational axis of the shearer drum and, through the agency of a special pivoting mechanism at the end of the path of travel of the mining machine, is pivoted into that peripheral zone of the shearer drum which is opposite the face area being mined.